38DD according to Nordstrom's fitter; 42DDD in my favorite Lane Bryant T-shirt bra. 5'7", 220 lbs, coming up on five years on HRT at 37 years old. However, I got most of that development within the first year - I've added about another cup size between year 2 and 4, and am still growing but very very slowly now.
(My mother is small, but my grandmother was curvy and my sister is 36DD at a much smaller 5'1".)